In combustion of fuel in an internal combustion engine, a blue flame, which is caused upon ignition by means of an ignition plug, usually converts into a red flame, which is caused upon combustion or the other colored flame. With respect to a measure to conduct analysis of a fuel combustion phenomenon in such an internal combustion engine, analysis of temperature of a chemical reaction or observation and analysis of behaviors or actions of a desired phenomenon, such as a bloodstream analysis utilizing a fluorescence microscope, there are conceivable measures to separate optically the light caused by such a phenomenon into a plurality of images having frequency bands for example of R, G and B (red, green and blue) so that these images are substantially simultaneously displayed on the single display screen.
These measures enable an operator to observe substantially simultaneously the respective image variation in R, G, and B on the single display screen to make a comparison. They are therefore considered to be effective in analysis of behaviors or actions of various kinds of phenomena.
In such measures, in case of a three-dimensional photogenic subject, the primary imaging of an image of the above-mentioned photogenic subject utilizing a field lens causes parallax in a depth direction in the primary imaging, with the result that accuracy in the imaging of the image based on the primary imaging and display thereof may be deteriorated, thus causing problems.
In a case where a half mirror, for applying a spectrographic step to the primary imaging caused by an objective lens so as to lead the light into a plurality of optical paths, is used to separate optically a transmitted light through the half mirror into a plurality of spectra having frequency bands, it is also conceivable that the amount of light for the transmitted image decreases upon transmission of the light through the half mirror, thus reducing the intensity of the light.
In an alternative case where a plurality of imaging elements perform imaging of a plurality of images, which have been optically separated into a plurality of frequency bands, respectively, to display them on a monitor, the images displayed on the monitor include discrepancies due to inherent characteristics in the respective imaging elements. It is therefore necessary to consider such discrepancies due to inherent characteristics in the imaging elements when conducting the image analysis, thus leading to an extremely complicated analysis and providing problems.
An object of the present invention, which was made in view of the above-described circumstances, is to provide a split-screen spectroscopic imaging apparatus that enables a single imaging element to perform a simultaneous imaging of a plurality of images into which the primary imaging of a photogenic subject having no or less parallax has been separated optically, at high accuracy and display these images on a monitor.